there is a wavebringer pet. It is called water elemental. But I forgot which boss you get him from but i know i have only seen like two people that have him and his traits are almost all epic so i am guessing he is hard to get

wavebringer drops the storm bats, or he use to, been long time since my Ice was there and won them then went inside and won the troll from the oni lolthat was quite a trip, h,, that was almost a year ago ! wow